1. Field of the Invention
The present invention relates to a machine vision system for dimensioning large or palletized freight of one or more pieces.
2. State of the Art
Systems for visually dimensioning objects are generally well known. See, for example, U.S. Pat. Nos. 4,731,853; 5,193,120; 4,929,843; 5,280,542; and 5,555,090, and “Optical Three-Dimensional Sensing for Machine Vision,” T. C. Strand, Optical Engineering, Vol. 24, No. 1, pp. 33-40. Such systems scan the object and the surrounding surface with a laser, and detect the laser reflected off of the scanned object, as well as off the surrounding surface, with a CCD camera. The detected laser image is analyzed to determine the dimensions of the object via triangulation.
Such systems for dimensioning objects have required a level of environmental structuring that has limited the potential application of automated dimensioning. In particular, such systems have been limited to substantially cuboidal objects and/or objects in known positions and, thus, have been unable to tolerate objects having highly noncuboidal shapes. Most often, limitations on the range of object size in relation to measurement resolution/accuracy have been imposed. In operation, these systems have been slow or awkward to use. Generally, the systems have been intolerant to variations in object reflectance, within or between objects, and/or ambient lighting. In order to reduce occlusion, such systems typically utilize movement, i.e., rotation, of the object and/or the sensing device, or require optical components to be located at the level of the object rather than being positioned remotely overhead. Finally, the common dimensioning systems have required costly hardware. The present invention is provided to solve these and other problems.